Gas-engine.



No. 669,737. Patented Mar. l2, mol.

THomsnN.

. GAS ENGINE. -ppueaion med Feb. 2s, 189s.)

(N0 Model.)

Il! Il IUI Il;

III--LW I IllllllllllllllL i ArtNr Prion.

LIHU THOMSON, OF SWAMPSOOTT, MASSACHUSETTS.

GAS-ENGINE.

SPECIFICATION forming part of Letters Patent No.. 669,737, dated March 12, i901. Application iiled February 23, 1898. Serial No. 671,240. lNo model.)

T a/ZZ whom t may oon/cern:

B e it knownthat I, ELIHU THOMSON, a citi` zen of the United States, residing in the town of Swampscott, county of Essex, and State of Massachusetts, have invented a newand useful Improvement in Gas-Engines, of which the following is a specification.

The present invention has for its object the simplifying' of working of certain types of engines suitable for the use of combustible gas or hydrocarbon vapor, such as vapor of oil or gasolene.

The invention applies to that type of engine in which the cycle of operations is similar to the Otto cycle in that a charge is indrawn on the first outward stroke, which is compressed on-the rst return stroke, the third or second outward stroke being the power-stroke and the fourth the return or exhaust stroke. In my invention, however, the charge of combustible is not drawn in or mixed with the charge of air during the intake-stroke, as above mentioned; but the charge of combustible is automatically delivered during the power-stroke to the body of compressed air, which has been brought to a high pressure on the compression-stroke. The time of this delivery may by a part of my invention be governed or controlled. In this way of working there is no combustible charge compressed.

Brieiiy the cycle as modied in my invention is as follows: First the forward motion of the piston or intake-stroke takes place at the same time that an inlet-valve is opened and admits air to fill the cylinder. During this stroke or at its completion a combustible charge of oil, gasolene, or other combustible is pumped into a small chamber in communication with the main cylinder by means of suitable passages,to be described. The intro- 4 duction therefore of the combustible charge charge passes into the receptacle or chamber, into which the fuel'gas or Vapor has already been pumped. The completion of the compression-stroke is made at such a high presi sure that the air, assisted by the heat of .the cylinder-walls, will be at a sufficiently high temperature to cause combustion when there is any combustible mixed with it. This pressure may be, according to the size of the engine, from three hundred to iive hundred pounds to the square inch, more or less. In the next or power stroke the return of the piston expands the highly-com pressed hot gas, and at the same instant the fuel charge, being driven by the portion of highly-compressed gas which has been forced into the receptacle containing it, passes out into the main cylinder and burns, thus adding to the volume of charge, but not increasing its pressure to any considerable extent. The combustion is then made during the power-stroke, the piston is driven forward, and finally on its return with an exhaust-valve open the waste gases are discharged ready to begin the cycle over again.

Another feature of my invention is the timing of the entrance of the combustible charge into the cylinder. This I do by causing a sudden marked drop of the compression-pressure at the instant desired, as just at the conclusion of the compression-stroke. When the charge of air is compressed to the highest point, a small valve may be opened to allow a certain portion of this charge to escape, as into a separate receptacle or chamber, and thus cause a sudden drop of pressure, the instant effect ofwhich is to give riseto an expulsion of the combustible charge and the mingling thereafter with the highly compressed and heated air, after which the power-stroke is finished in the ordinary manner.

I have illustrated my invention by embodying it in an engine shown in the drawings; but it must be understood that the invention is not specifically to the particular form of gas-engine there shown, but to the means employed in its operation in accordance with the cycle above stated and the method by which the operation is accomplished. I do not lay stress upon the details of mechanical construction, as they may be varied verv' IOO widely, and they are introduced here to illustrate the general action or the principle involved. Some of them, however, being valuable in connection with the engine of my invention are claimed in connection with the present case.

Figure 1 is a side elevation, partly in section, oi' an engine involving the present invention. Fig. 2 is a plan, part of which is in section through the line X X, Fig. l. Fig. 3 is simply an enlargement of the valves and working parts in the cylinder-head of Fig. l, made so as to be more clearly displayed. Fig. 4 is a modification of the details.

Any suitable crank or crank-shaft, as at K, is provided, furnished with a drivingwheel W, supported on suitable bearings. A connecting-rod R unites thecrank-pin with the moving piston P within the cylinder C in the ordinary way. This cylinder may be Water-jacketed, if desired, to avoid undue heating. A cylinder-head is shown, and at I an inlet-valve opening and closing communication between the cylinder-space and the external air. There is also the valve E, opening and closing communication with the eX- haust-pipe E2. The small valve E (shown above the exhaust-valve) may be called the timing valve. These parts are more clearly seen in Fig. 3, to which reference may be had for better-understanding. There is a little space or receptacle F back of the cylinder-space, which communicates with the said cylinder through a passage or passages. It also communicates with a feed-pump for combustible, which is indicated at O and which serves when operated to inject through suitable valves a fuelcharge into the space or receptacle F. This space or receptacle -communicates by passages, as at Q and J,

with the cylinder. The passage Q is governed by a valve-opening only, however, in case of any difference of pressure during the compression between the gases in the cylinder C and those in F. It tends, therefore, to equalize the pressures in F and C. It might be dispensed with, but is desirable where high-speed work is to be accomplished. It does not, however, permit free equalization of pressures between receptacles F and C in the reverse way-z'. e. from F to C-but closes in that direction, so that Whatever enters during th''tcompression into receptacle F by way of -\.`.-f-either the jet-passage J or the valve-covering passage Q must all ret-urn by the passage J. The passage J constitutes,in effect,an atomizer or mixing-jet, whereby whatever materials are found unmixed or separate in receptacle F must become thoroughly stirred together or mixed in passing from F to space C of the cylinder. Thus if F be divided by a wall, so as to have a space G distinct from the space H and with communication with the opening J only through fine passages and a quantity of oil has been sent into the receptacle F and exists in G, then on a sudden fall of pressure in the cylinder O there is an outrush of the compressed gas from H to J and an outrush of the oil or oil-vapor from G to J, where they are mixed and drawn violently into the cylinder-space. As a means for regulating the action of this, which may be called the atomizing7 or mixing jet J, I have shown an adjustable com mingling-valve, controlled by head N, which tends when screwed backward or forward to adjust the size or relation between the passages from Gand ILrespectively, so as to prevent a too sudden rejection of the combustible charge G on the second outward or power stroke of the piston P.

Similar parts, in so far as they are shown in Fig. 2, are lettered as in Figs. 1 and 3. It will be seen that the small valve V, if opened, lwould connect the cylinder-space with the exhaust passage or pipe. This is one way of arranging the time of drop-pressu re by valve V. In Fig. 4, however, this valve opens communication from cylinder-space C into a special receptacle D, so that the gas which is thus allowed to escape from the cylinder C and cause a drop of pressure is held in D for subsequent return and expansion during the power-stroke, valve V being kept open during that stroke only. *Y For the proper working of the valves in theisequence, demanded by the cycle above stated, suitable cams may be mounted upon a cam-shaft L, which cam-shaft is driven in definite relation to the motions of the crank K-that is, a gearing is provided which keeps the cam-shaft L in definite working relation to the main shaft. In-general this gearing reduces the speed of the cam-shaft L to onehalf the usual speed, as is customary in gasengines. This shaft may also carry a governor M for controlling the speed by causing the admission -cams for combustible or the pump O to miss its stroke or diminish the amount of its action in throwing in combustible. This, however, is easily accomplished in many different ways and is not an essential feature of the present invention and is here simply described to make clear the operations. The cam which governs valve I opens valve I during the forward motion of the piston or the intake-stroke, allowing air to ll the cylinder. During this stroke or near its conclusion the cam on the cam-shaft L, which operates the pump O, feeding combustible, which cam is marked a, in Fig. l and works upon lever l, operates the pump and forces a charge of combustible into receptacle F just before the compression -stroke is eifected. This pumping of combustible is, however, governed by the governor M, which, if the speed be too high, raises one end of the small lever Z9 and disengages by small lever d the lever l from the pump-piston, the return of which is effected bya spring after any stroke. The compression-stroke begins with all the valves shut, and during the stroke the valve .governing passage Q may be forced open by the rush of gas under compression tending to reach receptacle F on account of the pas- IIO sages through J being too small or restricted. The compression-stroke being carried on, a high pressure is obtained sufficient to heat the compressed air in the cylinder sufficiently to cause the combustion of any combustible sent thereinto, and this stroke is followed by the outward motion of the piston, at which `time the valve Q closes and the discharge from the receptacle F begins. This discharge mixes or atomizes the fuel passing out through the opening J into the cylinder, and combustion takes place within the cylinder-space during the power-stroke. This action might be a little late, owing to the fact that not untilthe piston begins to leave its farthest inward position and not until the crank has therefore passed well over the dead-center does the jet J deliver fuel. To accelerate this de1ivery, a suitable cam e operates the small valve V to relieve the pressure in C slightly at or about the` time the crank is on dead-center and space Within the cylinder C has reached its smallest volume. This provokes the discharge from the receptacle F, and, as stated before, the escape or lowering of pressure from valve V may be tempo- Arary by providing a restricted chamber D,

into which the excess escapes. If the cam e be made so as to keep the valveV open during the power-stroke, the stored pressure in chamber D, Fig. 4, will add its expansion effects to those of the gas within the cylinder C itself, and the chamber D will be ready after the closure of valve V for the renewal of the actions. If the connection of valve V opens into the outside air or inside pipe E2, as in Fig. l, the opening thereof is but momentary, followed by immediate closure, so as not to allow much fallin pressure at C, which would mean a loss of effectiveness. During the power-stroke or second forward motion of the piston P the compressed gas in receptacle F discharges itself almost completely, and the exhaust-valve E is then opened by a suitable cam f while the return or exhaust stroke is effected, which drives out the products of combustion and waste gases ready for the beginningof the same set of operations.

I am aware that it is not new to draw in a charge of air, compress the same, and then inject by suitable pumps a quantity of fuel, gas, or vapor, which burns during the powerstroke; but in my invention the injection of the fuel takes place at a time when there is no back pressure opposing its forward movement, and the actions occurring in the cylinder during compression are made the means for the discharge of fuel into the cylinder after compression without the aid of external injecting appliances worked from the outside, and thus I am enabled to obtain, with great simplicity of parts, effects which have hitherto been unattainable.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In an internal-combustion engine of the kind described, a cylinder for receiving a compressed-air charge, as produced by the motion of its piston after the intake, a cylinder-head having within it a chamber for the reception of a charge of oil fuel and a portion of the compressed-air charge from the cylinder, said chamber being provided with a valve opening toward it from the cylinder-space in combination with an atomizing-jet, the openings to which are at the bottom of said receptacle, substantially as described.

2. In an internal-combustion engine, having a cylinder and a piston traversing the cylinder-space, the cylinder-head or a portion of the cylinder-wall having combined with it an atomizing-jet and a fuel-receptacle as described, and an inlet-valve from the cylinder-space to the receptacle,with means such as a pump for pumping oil into the receptacle when little or no pressure exists therein, substantially as described.

In witness whereof I have hereunder set my hand this 21st day of February, 1898.

ELIIIU THOMSON.

Witnesses:

DUGALD MCKILLOP, HENRY O. WESTENDARP. 

